The chromosomal number in the meiocytes of housefly is :

Options

A. 8
B. 12
C. 21
D. 23

Answer

To determine the chromosomal number in the meiocytes of houseflies, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Term "Meiocytes":**
- Meiocytes are specialized cells that undergo meiosis to produce gametes. They are diploid (2n) cells that contain two sets of chromosomes.

2. **Identify the Chromosomal Number in Houseflies:**
- The question asks for the chromosomal number in the meiocytes of houseflies. It is important to know the diploid number of chromosomes for houseflies.

3. **Know the Options Provided:**
- The options given are 8, 12, 21, and 23. We need to determine which of these represents the diploid number of chromosomes in houseflies.

4. **Research the Chromosomal Number of Houseflies:**
- Houseflies (Musca domestica) have a diploid chromosomal number of 12. This means that in their meiocytes, which are diploid, there are 12 chromosomes.

5. **Conclusion:**
- Since the meiocytes of houseflies contain 12 chromosomes, the correct answer is **12**.

### Final Answer:
The chromosomal number in the meiocytes of housefly is **12** (Option B).

---